Today, Yayoi Kusama is an art-world superstar, with museum-goers around the world lining up for hours for the chance to take photographs of—and with—her mirrored Infinity Rooms and polka-dotted pumpkins. And yet, the Japanese artist has lived in a mental hospital since the 1970s, suggesting an unseen dark side to her colorful universe. As a new documentary reveals, the road to success was a long and winding one that tested the artist’s drive, resiliency, and, ultimately, her sanity.